physical education. n. (Education) training and practice in sports, gymnastics, etc, as in schools and colleges. Abbreviation: PE. physâ²ical educaâ²tion. n. instruction in sports, exercise, and hygiene, esp. as part of a school or college program.
3. Stress/injury. Stress on the tissues or any type of injury in the mouth can cause canker sores. Since the sores are actually tiny ulcers, they can be caused by any kind of hard brushing or eating something that can cause bruises or lead to tissue inflammation in the mouth.
A common cause is from bleeding, because the pigment in red blood cells contains iron. If you bite your tongue by accident, suffer trauma to the mouth, or have gum disease which can cause spontaneous bleeding from inflamed gums, then you will likely have a metal taste for a while, or notice it now and again.